In automobile exhaust systems, a series of pipes are interconnected to conduct the flow of hot exhaust gases from the engine to the tailpipe of the automobile. The pipes consist of a manifold pipe and a pipe leading from the exhaust manifold, which are interconnected with flanged members.
This portion of the exhaust system transmits the exhaust gas directly from the engine to a pipe or passage leading to the catalytic converter. The flanged connection between these pipes radiates a large amount of thermal energy, which can be detrimental to some of the more sensitive components that are positioned near this joint. These components might include electrical wires and pipes carrying fluid for the engine.
The flanged joint is insulated from the surrounding environment by a heat shield that is attached directly to one or both of the flange members and is separate from the gasket, which is compressed between the flange members. The gasket member, of course, prevents the direct leakage of exhaust fumes as the exhaust gases pass through the pipe and the shield protects the environment.
The shield requires extensive machining through the flanges so that the shield might be attached thereto, The heat shield also requires additional work by the assembler to place the shield in the proper location, and if not securely fastened, can result in a rattle or other disturbing noise within the engine compartment.
It has been proposed to provide a single assembly for the heat shield and gasket. One such device is shown in U.S. Ser. No. 09/999,7975 filed Oct. 31, 2001, now U.S. Pat. No. 6,811,159, assigned to General Motors, one of the assignees of the present invention.